IS 901 — Specification for Couplings, Double Male And Double Female, Instantaneous Pattern For Fire Fighting

IS 901: Scope - Key Specifications & Requirements

Scope:
IS 901 covers couplings made from copper alloys with specified materials, dimensions, and hydraulic test requirements.

1. Material Specifications (Clause 2.1):

*Includes leaded tin bronze, high tensile brass, leaded brass, naval brass, aluminium alloys, phosphor bronze, and stainless steel wires.

2. Hydraulic Test Requirement (Clause 4.1):

• Coupling subjected to 2.1 MN/m² (21 kgf/cm²) pressure for 2 minutes.
• No leakage or sweating allowed.

3. Dimensions:

• Refer to Fig. 1 and Fig. 2 (typical shapes and essential dimensions).

4. Conformity (Clause 7.1):

• Each coupling must meet all requirements in the standard.

Summary Diagram:

flowchart TD
    A[Material Selection] --> B[Manufacturing (Casting/Forging)]
    B --> C[Dimension Check (Fig.1 & Fig.2)]
    C --> D[Hydraulic Pressure Test (2.1 MN/m² for 2 min)]
    D --> E{No Leakage?}
    E -->|Yes| F[Conformity Confirmed]
    E -->|No| G[Reject/Remanufacture]

Note: Always refer to the latest IS 901 edition and related IS codes for detailed dimensions and testing procedures.

IS 901: Key Materials Specifications

1. Copper Alloys (Clause 2.1)

• *Lead tin bronze ingots and castings
• +High tensile brass ingots and castings
• #Leaded brass ingots and castings
• §Naval brass rods and sections (for machining & forging)
• ||Brass gravity die casting ingots and castings

2. Aluminium Alloys (Clause 2.2)

• Aluminium alloys for castings shall conform to IS Designation 4450, 4225, or 4600 as per IS:617-1975*.

3. Hydraulic Test (Clause 4.1)

• Couplings must withstand 2.1 MN/m² (21 kgf/cm²) hydraulic pressure for 2 minutes without leakage or sweating.

Summary Table for Copper Alloys

If you need detailed mechanical properties or chemical composition, refer to respective IS standards mentioned.

IS 901: Shape and Dimensions of Instantaneous Couplings

• Typical shapes and essential dimensions are specified in Fig. 1 (Double Male Coupling) and Fig. 2 (Double Female Coupling) of the standard.
• All dimensions are in millimetres (Clause 3.1, 11.3).
• Key dimension example from Fig. 1:
  • Diameter: 35 ± 1 mm
  • Thickness: 6.0 ± 0.5 mm

Materials (Clause 2.1)

Summary:

• Use Fig.1 and Fig.2 for exact shape and dimensional details.
• Dimensions must be strictly adhered to for proper fit and hydraulic sealing.
• Material specifications ensure durability and corrosion resistance.

flowchart LR
    A[Start: Select Coupling Type] --> B{Male or Female?}
    B -->|Male| C[Refer Fig.1: Double Male Coupling]
    B -->|Female| D[Refer Fig.2: Double Female Coupling]
    C --> E[Check Dimensions (e.g., 35±1 mm dia)]
    D --> E
    E --> F[Select Material Grade as per Clause 2.1]
    F --> G[Manufacture & Inspect per IS 901]

Hydraulic Test Requirement — IS 901

Clause 4.1 specifies the hydraulic test for couplings as follows:

• Test Pressure: 2.1 MN/m² (21 kgf/cm²)
• Duration: 2 minutes
• Acceptance Criteria: No leakage or sweating shall be observed.

Summary Table

Additional Specifications

• Materials conform to relevant IS standards for copper alloys (e.g., IS 318, IS 304, IS 291, IS 1264).
• Couplings must meet dimensional and shape requirements as per Figures 1 and 2 of IS 901.
• The test ensures the coupling's integrity under pressure, verifying manufacturing quality.

flowchart LR
  A[Coupling] --> B[Apply Hydraulic Pressure 2.1 MN/m²]
  B --> C{Duration 2 minutes}
  C --> D{Check Leakage}
  D -- No leakage --> E[Pass]
  D -- Leakage --> F[Fail]

Note: Always perform tests in controlled conditions and follow safety protocols.

IS 901: Workmanship and Finish - Key Points

1. Workmanship (Clause 5.1)

• All fittings must be free from burrs, sharp edges, porosity, blow-holes, scales, cracks, and other defects.
• Forgings and castings must be sound and not repaired to hide defects.
• Waterways inside fittings should have a smooth finish.
• Exposed aluminium surfaces require an anodized finish.
• Threaded aluminium alloy parts must be coated with molybdenum-based grease.

2. Material Specifications (Clause 2.1, Table 2)

3. Testing (Clause 4.1)

• Couplings must withstand hydraulic pressure of 2.1 MN/m² (21 kgf/cm²) for 2 minutes without leakage.

Summary Diagram of Workmanship Process

flowchart LR
    A[Raw Casting/Forging] --> B[Inspection for Defects]
    B -->|No Defects| C[Machining & Finishing]
    B -->|Defects Found| D[Reject or Recast]
    C --> E[Surface Treatment]
    E --> F[Final Inspection]
    F -->|Pass| G[Coating & Greasing (if Aluminium)]
    G --> H[Ready for Use]

Note: Follow referenced IS standards for detailed material properties and testing methods.

IS 901 - Marking Requirements for Couplings

Key Marking Specifications (Clause 6.1)

Each coupling must be clearly and permanently marked with:

• Manufacturer's name and trade-mark
• Year of manufacture
• Type of material

Standard Mark (Clause 6.1.1)

• Couplings may bear the BIS Standard Mark indicating compliance with IS 901.
• Use of the Standard Mark is governed by the Bureau of Indian Standards Act, 1986.
• It assures quality under BIS inspection and quality control.

Material Grades for Copper Alloys (Clause 2.1)

Additional Notes

• Couplings must withstand hydraulic pressure test:
  2.1 MN/m² (21 kgf/cm²) for 2 minutes without leakage (Clause 4.1).

Summary Diagram: Marking Information on Coupling

graph LR
A[Coupling] --> B[Manufacturer's Name & Trade-mark]
A --> C[Year of Manufacture]
A --> D[Type of Material]
A --> E[Standard Mark (optional)]

This ensures traceability, material verification, and quality assurance per IS 901.

IS 901: Criteria for Conformity (Clause 7.1)

• Each coupling shall conform strictly to the requirements specified in IS 901.
• Couplings must meet material, dimensional, and performance criteria as per the standard.
• Materials for couplings typically include Copper Alloys conforming to:
  • Sand castings: Grade LTB 2 (IS 318:1981) or Grade HTB 1 (IS 304:1981)
  • Die castings: Grade 3 (IS 292:1983)
  • Hot forgings: Grade 1 (IS 291:1977)
  • Gravity die castings: IS 1264:1981

Key Points:

• Couplings must bear the Standard Mark (Clause 6.1.1) to assure compliance.
• BIS continuously monitors and inspects for conformity.
• No reproduction of the standard without BIS permission.

Summary Table: Material Grades for Couplings

This ensures couplings meet strength, durability, and safety standards for plumbing and mechanical applications.